Jiming Zhang1,2, John Fischer1, Lizette Warner3, Aytekin Oto4, Pei-Herng Hor2, Raja Muthupillai1. 1. Department of Diagnostic and Interventional Radiology, CHI St. Luke's Health, Houston, Texas, USA. 2. Department of Physics and Texas Center for Superconductivity at University of Houston, Houston, Texas, USA. 3. Philips Healthcare, USA. 4. University of Chicago Medical Center, Chicago, Illinois, USA.
Abstract
PURPOSE: To estimate the local thermal conductivity of uterine fibroid in vivo at a high temperature range (60-80°C) typically encountered in magnetic resonance imaging-guided high-intensity focused ultrasound (MRgHIFU) surgery. The thermal conductivity of uterine fibroids in vivo is unknown and knowledge about tissue thermal conductivity may aid in effective delivery of thermal energy for ablation. MATERIALS AND METHODS: All subjects (nine women) provided written informed consent to participate in this Institutional Review Board-approved study. A total of 10 fibroids were treated using MRgHIFU surgery with real-time temperature monitoring during both heating and cooling periods. The local thermal conductivity was determined by analyzing the spatiotemporal spread of temperature during the cooling period. RESULTS: The thermal conductivity of MRgHIFU-treated uterine fibroids was 0.47 ± 0.07 W·m(-1) ·K(-1) (range: 0.25∼0.67 W·m(-1) ·K(-1) ) which is slightly lower than the reported value for skeletal muscle at temperatures of <40°C (0.52 to 0.62 W·m(-1) ·K(-1) ). CONCLUSION: It is possible to estimate the thermal conductivity of uterine fibroids in vivo from the spatiotemporal spread of temperature around the HIFU focus during the cooling period.
PURPOSE: To estimate the local thermal conductivity of uterine fibroid in vivo at a high temperature range (60-80°C) typically encountered in magnetic resonance imaging-guided high-intensity focused ultrasound (MRgHIFU) surgery. The thermal conductivity of uterine fibroids in vivo is unknown and knowledge about tissue thermal conductivity may aid in effective delivery of thermal energy for ablation. MATERIALS AND METHODS: All subjects (nine women) provided written informed consent to participate in this Institutional Review Board-approved study. A total of 10 fibroids were treated using MRgHIFU surgery with real-time temperature monitoring during both heating and cooling periods. The local thermal conductivity was determined by analyzing the spatiotemporal spread of temperature during the cooling period. RESULTS: The thermal conductivity of MRgHIFU-treated uterine fibroids was 0.47 ± 0.07 W·m(-1) ·K(-1) (range: 0.25∼0.67 W·m(-1) ·K(-1) ) which is slightly lower than the reported value for skeletal muscle at temperatures of <40°C (0.52 to 0.62 W·m(-1) ·K(-1) ). CONCLUSION: It is possible to estimate the thermal conductivity of uterine fibroids in vivo from the spatiotemporal spread of temperature around the HIFU focus during the cooling period.
Authors: Jingfei Liu; Josquin Foiret; Douglas N Stephens; Olivier Le Baron; Katherine W Ferrara Journal: Phys Med Biol Date: 2016-06-29 Impact factor: 3.609